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How do I save external JSON data to a JavaScript variable? [duplicate]

I have this JSON file I generate in the server I want to make accessible on the client as the page is viewable. Basically what I want to achieve is:
I have the following tag declared in my html document:
<script id="test" type="application/json" src="http://myresources/stuf.json">
The file referred in its source has JSON data. As I've seen, data has been downloaded, just like it happens with the scripts.
Now, how do I access it in Javascript? I've tried accessing the script tag, with and without jQuery, using a multitude of methods to try to get my JSON data, but somehow this doesn't work. Getting its innerHTML would have worked had the json data been written inline in the script. Which it wasn't and isn't what I'm trying to achieve.
Remote JSON Request after page loads is also not an option, in case you want to suggest that.

You can't load JSON like that, sorry.
I know you're thinking "why I can't I just use src here? I've seen stuff like this...":
<script id="myJson" type="application/json">
{
name: 'Foo'
}
</script>
<script type="text/javascript">
$(function() {
var x = JSON.parse($('#myJson').html());
alert(x.name); //Foo
});
</script>
... well to put it simply, that was just the script tag being "abused" as a data holder. You can do that with all sorts of data. For example, a lot of templating engines leverage script tags to hold templates.
You have a short list of options to load your JSON from a remote file:
Use $.get('your.json') or some other such AJAX method.
Write a file that sets a global variable to your json. (seems hokey).
Pull it into an invisible iframe, then scrape the contents of that after it's loaded (I call this "1997 mode")
Consult a voodoo priest.
Final point:
Remote JSON Request after page loads is also not an option, in case you want to suggest that.
... that doesn't make sense. The difference between an AJAX request and a request sent by the browser while processing your <script src=""> is essentially nothing. They'll both be doing a GET on the resource. HTTP doesn't care if it's done because of a script tag or an AJAX call, and neither will your server.

Another solution would be to make use of a server-side scripting language and to simply include json-data inline. Here's an example that uses PHP:
<script id="data" type="application/json"><?php include('stuff.json'); ?></script>
<script>
var jsonData = JSON.parse(document.getElementById('data').textContent)
</script>
The above example uses an extra script tag with type application/json. An even simpler solution is to include the JSON directly into the JavaScript:
<script>var jsonData = <?php include('stuff.json');?>;</script>
The advantage of the solution with the extra tag is that JavaScript code and JSON data are kept separated from each other.

It would appear this is not possible, or at least not supported.
From the HTML5 specification:
When used to include data blocks (as opposed to scripts), the data must be embedded inline, the format of the data must be given using the type attribute, the src attribute must not be specified, and the contents of the script element must conform to the requirements defined for the format used.

While it's not currently possible with the script tag, it is possible with an iframe if it's from the same domain.
<iframe
id="mySpecialId"
src="/my/link/to/some.json"
onload="(()=>{if(!window.jsonData){window.jsonData={}}try{window.jsonData[this.id]=JSON.parse(this.contentWindow.document.body.textContent.trim())}catch(e){console.warn(e)}this.remove();})();"
onerror="((err)=>console.warn(err))();"
style="display: none;"
></iframe>
To use the above, simply replace the id and src attribute with what you need. The id (which we'll assume in this situation is equal to mySpecialId) will be used to store the data in window.jsonData["mySpecialId"].
In other words, for every iframe that has an id and uses the onload script will have that data synchronously loaded into the window.jsonData object under the id specified.
I did this for fun and to show that it's "possible' but I do not recommend that it be used.
Here is an alternative that uses a callback instead.
<script>
function someCallback(data){
/** do something with data */
console.log(data);
}
function jsonOnLoad(callback){
const raw = this.contentWindow.document.body.textContent.trim();
try {
const data = JSON.parse(raw);
/** do something with data */
callback(data);
}catch(e){
console.warn(e.message);
}
this.remove();
}
</script>
<!-- I frame with src pointing to json file on server, onload we apply "this" to have the iframe context, display none as we don't want to show the iframe -->
<iframe src="your/link/to/some.json" onload="jsonOnLoad.apply(this, someCallback)" style="display: none;"></iframe>
Tested in chrome and should work in firefox. Unsure about IE or Safari.

I agree with Ben. You cannot load/import the simple JSON file.
But if you absolutely want to do that and have flexibility to update json file, you can
my-json.js
var myJSON = {
id: "12ws",
name: "smith"
}
index.html
<head>
<script src="my-json.js"></script>
</head>
<body onload="document.getElementById('json-holder').innerHTML = JSON.stringify(myJSON);">
<div id="json-holder"></div>
</body>

place something like this in your script file json-content.js
var mainjson = { your json data}
then call it from script tag
<script src="json-content.js"></script>
then you can use it in next script
<script>
console.log(mainjson)
</script>

Check this answer: https://stackoverflow.com/a/7346598/1764509
$.getJSON("test.json", function(json) {
console.log(json); // this will show the info it in firebug console
});

If you need to load JSON from another domain:
http://en.wikipedia.org/wiki/JSONP
However be aware of potential XSSI attacks:
https://www.scip.ch/en/?labs.20160414
If it's the same domain so just use Ajax.

Another alternative to use the exact json within javascript. As it is Javascript Object Notation you can just create your object directly with the json notation. If you store this in a .js file you can use the object in your application. This was a useful option for me when I had some static json data that I wanted to cache in a file separately from the rest of my app.
//Just hard code json directly within JS
//here I create an object CLC that represents the json!
$scope.CLC = {
"ContentLayouts": [
{
"ContentLayoutID": 1,
"ContentLayoutTitle": "Right",
"ContentLayoutImageUrl": "/Wasabi/Common/gfx/layout/right.png",
"ContentLayoutIndex": 0,
"IsDefault": true
},
{
"ContentLayoutID": 2,
"ContentLayoutTitle": "Bottom",
"ContentLayoutImageUrl": "/Wasabi/Common/gfx/layout/bottom.png",
"ContentLayoutIndex": 1,
"IsDefault": false
},
{
"ContentLayoutID": 3,
"ContentLayoutTitle": "Top",
"ContentLayoutImageUrl": "/Wasabi/Common/gfx/layout/top.png",
"ContentLayoutIndex": 2,
"IsDefault": false
}
]
};

While not being supported, there is an common alternative to get json into javascript. You state that "remote json request" it is not an option but you may want to consider it since it may be the best solution there is.
If the src attribute was supported, it would be doing a remote json request, so I don't see why you would want to avoid that while actively seeking to do it in an almost same fashion.
Solution :
<script>
async function loadJson(){
const res = await fetch('content.json');
const json = await res.json();
}
loadJson();
</script>
Advantages
allows caching, make sure your hosting/server sets that up properly
on chrome, after profiling using the performance tab, I noticed that it has the smallest CPU footprint compared to : inline JS, inline JSON, external JS.

How do I append a query parameter to my URL using Javascript?

I am building a web app and I am using Firebase to store my user's data in Cloud Firestore. There is a page on my web app that allows users to view their documents from Cloud Firestore. I would like to add a query parameter to the end of my URL on view.html so I can take that query parameter value and use it to search for a document.
I have been searching online to find possible solutions. So far I have come across a few videos on the topic, but they haven't been going into the depth I have been needing. For example, this video shows how to add and get query parameters from a URL, but it only shows how to log those changes in the console. How would I make that my URL?
I've also be browsing Stackoverflow for solutions. This Stackoverflow post asks a similar question, however, many of the solutions in the answers causes view.html to reload on a loop. Why would this be, and if this is a possible solution, how would I stop this from happening.
How would I go about appending and fetching URL query parameters in Javascript?

You say you want to do this in javascript, so I assume the page itself is building/modifying a link to either place on the page or go to directly via javascript.
In javascript in the browser there is the URL object, which can build and decompose URLs
let thisPage = new URL(window.location.href);
let thatPage = new URL("https://that.example.com/path/page");
In any case, once you have a URL object you can access the parts of it to read and set the values.
Adding a query parameter uses the searchParams attribute of the URL, where you can add parameters with the .append method — and you don't have to worry about managing the ? and & … the method takes care of that for you.
thisPage.searchParams.append('yourKey', 'someValue');
This demonstrates it live on this page, adding search parameters and displaying the URL at each step:
let here = new URL(window.location.href);
console.log(here);
here.searchParams.append('firstKey', 'theValue');
console.log(here);
here.searchParams.append('key2', 'another');
console.log(here);

I have solved this issue in the simplest way. It slipped my mind that I could link to view.html by adding the search parameter to the URL. Here's what I did:
On index.html where I link to view.html, I created the function openViewer();. I added the parameter to the end of URL href.
function openViewer() {
window.location.href = `view.html?id={docId}`;
}
Then on view.html, I got the parameter using URLSearchParameters like so:
const thisPage = new URL(window.location.href);
var id = thisPage.searchParams.get('id');
console.log(id)
The new URL of the page is now "www.mysite.com/view.html?id=mydocid".

You can try to push state as so in the actual view.html
<script>
const thisPage = new URL(window.location.href);
window.history.pushState("id","id",thisPage);
</script>

Retrieve part of json file from an external website (sparkfun)

This question might be quite specific to sparkfun, but I still wish to make it as a general question due to my limited experience in javascript.
I have been using the follow html and javascript (d3.js) file to load json data from sparkfun data server:
index.html
<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var data_sensor;
var url = "https://data.sparkfun.com/output/w5nEnw974mswgrx0ALOE.json"
d3.json(url, function (error,json) {
if (error) throw error;
data_sensor=json;
console.log(data_sensor)
})
</script>
</body>
After running the script, i will end up with all data array stored in variable data_sensor for post-analyse.
What i wish to do now is to create a dash board that downloads and stores only the latest value. i understand that i could just use the first value in the data_sensor to do so (i.e., data_sensor[0]) but such method becomes quite inefficient with the growth of data.
Thanks!

When I've wanted to load JSON from somewhere I've always used jQuery:
Import jQuery like this:
<script src="jquery-3.2.1.min.js"></script>
Then you can do something like this to get your JSON file:
var data_sensor;
var url = "https://data.sparkfun.com/output/w5nEnw974mswgrx0ALOE.json"
$.getJSON(url, function(data) {
data_sensor = data;
console.log(data_sensor)
});
Hope that helps!

Not an expert here, but their docs state tat you can use paging to get the first 250kb of data:
var url = "https://data.sparkfun.com/output/w5nEnw974mswgrx0ALOE.json?page=1";
You can get your first object/set of data, and I'm afraid there's no general way to take only part of any API response - request is request, it could send you every possible data depending on architecture, from "OK" string to 200MB of data. Carefully reading docs is your best bet.

Using arrays in JavaScript

I am trying to write a program in javascript in which there is a list of products in an array, and they are sorted in alphabetical order. However, when I enter the code into notepad, and load it up in the website format, it just displays the code I have entered, with no formatting
var products = ["Printer","Tablet","Router","Speakers","Mouse"];
Arrays.sort(products);
System.out.println(Arrays.toString(products));
This is the code exactly as it is in notepad, and in the website bit, it is displayed as one long line of all the programming

You have to surround your code with a script tag:
<script type="text/javascript">Your_code_here</script>
Furthermore System.out.println and Arrays.toString are Java functions. It seems like you have Java confused with JavaScript. I think what you are trying to do is:
<!DOCTYPE html>
<html>
<body>
<script>
var products = ["Printer", "Tablet", "Router", "Speakers", "Mouse"];
products.sort();
var productsString = products.join(" ");
document.write(productsString);
</script>
</body>
</html>

If you point a browser at a URL which returns JavaScript source code, then it will display the JavaScript source code (generally not as a single line those, that suggests a further error in which you are serving it to the browser with a Content-Type: text/html header instead of Content-Type: application/javascript).
If you want to execute client side JavaScript then you need to write an HTML document and import the JavaScript using a <script> element.
Your code will then fail because Arrays and System will be undefined.

Javascript not like java ..to use helper functions in javascript as ..sort,filter,reserve....you can use underscore.js library

Output data from TaffyDB

I'm new to JavaScript and am trying to build a script that performs some data management activities(Basically query based data fetching from a database and then displaying it on a webpage).
I generally would do this on the server side with PHP and mysql but my boss want's to see a "sample" before investing in servers etc. (He has no technical knowledge regarding PHP,MySQL etc)
Now without a server I was looking for a way to build a similar system on the client side mostly via javascript. Just to demonstrate the logic I plan on implementing.
For the database part I decided to use TaffyDB, however am having issues getting an output from the database(Display the data on a webpage)
Here's my code
<!DOCTYPE html>
<html>
<head>
<script src="taffydb-master\taffy.js"></script>
<script>
var companies = TAFFY
([
{name:"New York",state:"WA"},
{name:"New Shire",state:"WE"},
{name:"Las Vegas",state:"NV"},
{name:"Boston",state:"MA"}
]);
var cities = new Array();
var cities = companies().select("name");
</script>
</head>
<body>
<script>
document.write = (cities[1]);
</script>
</body>
</html>
I know there's some silly mistake in there but really can't find it. I tried using the developer's tools (Mozilla's default one) but it returns no issues. I basically just get a blank white page when I load this file.

You are using document.write incorrectly. It is a method.
If you change your code to:
<script>
document.write(cities[1]);
</script>
then you will get this output:
New Shire
Also, you should probably wrap the output in some element like so:
<script>
document.write("<p>" + cities[1] + "</p>");
</script>